The combination of ports made on the piston skirt with ports made on the cylinder liner is a common practice; the poor scavenging efficiency and the increased pumping loss are among the disadvantages, as well as the symmetric timing: if a port is open at 80 deg before the TDC (Top Dead Center), it will also be open at 80 deg after the TDC.
The use of a one way, or reed, valve is another common solution. The inertia of the reed valve, the impact loads on the reed valve leaves, the noise, the need for a pressure difference at the two side of the reed valve, the limited reliability etc are among the disadvantages.
The use of poppet valves is another way, but they need space, cams, springs, synchronization gearing etc, while they have low flow capacity and low rev limit.
The use of a disk valve (or drum valve) formed on the crankshaft is another way; ports on the disk valve cooperate with stationary ports on the casing. The dead volume of the crankcase is unavoidably large (the volume inside the piston is added to the crankcase volume). The location of the wrist pin makes the cooling of the backside of the piston crown difficult. Each piston needs its own crankcase, etc.
It is an object of the present invention to address the above disadvantages. Accordingly, there is provided a “connecting rod valve” for reciprocating piston engines and pumps as defined in the appended claims.